swift or house martin

we just had dozens of birds, swifts, house martins or others, flying around the apex to our house for around 10 mins. they then dispersed (catching food on the wing no doubt) I'm trying to identify them, a wonderful sight  (0830 am). However I'm also wondering if they have nested under the eaves into the loft area as that is the area they went to mostly. It's a large house, very new and there are potentially lots of access areas. We live by farmland in Cornwall. I manged to get a video but cannot identify them as I'm no expert on birds.